21085550 has 12 divisors (see below), whose sum is σ = 39219216. Its totient is φ = 8434200.

The previous prime is 21085543. The next prime is 21085567. The reversal of 21085550 is 5558012.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 210806 + ... + 210905.

It is an arithmetic number, because the mean of its divisors is an integer number (3268268).

Almost surely, 2^21085550 is an apocalyptic number.

21085550 is a deficient number, since it is larger than the sum of its proper divisors (18133666).

21085550 is a wasteful number, since it uses less digits than its factorization.

21085550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 421723 (or 421718 counting only the distinct ones).

The product of its (nonzero) digits is 2000, while the sum is 26.

The square root of 21085550 is about 4591.9004780156. The cubic root of 21085550 is about 276.2665544293.

The spelling of 21085550 in words is "twenty-one million, eighty-five thousand, five hundred fifty".